Can I use a string in comparison statement?

Summary:I just tried to compare value initially but it didnt't reflected, If I place #Missing in the code inside if condition the code gets executed, if I place any value like 1,2,3,4 it is not executing.

Also provide solution to compare string intead of number

Eg: If ("Allocation"->"FN_000" == 1) how can I use a string in the place of 1, please share if there is any syntax for it.

Content (required):

FIX (D_0000, E_010,/* FN_000,*/ FD_00000, IC_000, @Relative(YearTotal, 0)/*, @relative("OFS_Total Plan", 0)*/, OEP_Forecast, OEP_Working, FY23, USD) 

  "FN_000" (

    If ("Allocation"->"FN_000" == ?)

      "FN_200"->OFS_Calculated = ("FN_000"->OFS_Calculated) * 0.5;